AMHERST, N.H. (AP) — A fiery Jeb Bush defended his foreign policy strategies Saturday in the face of criticism from a Donald Trump supporter who showed up at one of Bush’s town hall meetings.

Christopher Mazerall, a town chairman for Trump’s New Hampshire campaign, said he decided to come by Bush’s event on his way to make calls for Trump’s presidential bid.

“You’re willing to engage in a world war with Russia over foreign interests in Syria,” Mazerall told Bush from the crowd. “How is that not treason?” His assertion centered on Bush’s call for the U.S. to support a no-fly zone in Syria, where Russia is engaged in the country’s years-long civil war.

“The no-fly zone, in my mind, should send a signal to Russia we’re back in the game,” Bush replied. “Mr. Trump has suggested we should just outsource this and let Russia destroy ISIS.” He declared: “We should not outsource that to the Russians; they’re not our friends.”

The exchange lasted several minutes, with Mazerall also challenging Bush’s earlier statement that it would violate international standards under the Geneva Conventions to bomb the Islamic State group without regard for the killing of innocent civilians.

“You said it would be against the Geneva Convention to attack ISIS where their families are,” Mazerall said, using an acronym for the Islamic State group.

“Yeah, killing innocent people would be a war crime,” Bush shot back. “No president would allow for the killing of innocents as a designed strategy of the United States, my friend — no one.”

Bush has made foreign policy a centerpiece of his Republican campaign, advocating for a stronger response to the Islamic State group that could include putting U.S. troops on the ground in Syria. He’s tangled with Trump repeatedly on foreign policy, slamming the businessman’s call to ban Muslims from entering the United States and Trump’s comments that he would get along well with Russian President Vladimir Putin.

“If the world sees the United States as backing down from a despot like Putin or a candidate that suggests that Putin is our ally because he’s a strong man or something like that — that creates chaos in the world,” Bush said.

Mazerall said he appreciated Bush’s willingness to answer his questions but was unimpressed by Bush’s responses.